What is a measure of speech intelligibility that demonstrates the frequency contributing most significantly to speech intelligibility?

The Speech Intelligibility Index (SII) at 2000 Hz is a critical measure because it identifies the frequency range that plays a pivotal role in understanding speech. The 2000 Hz frequency is part of the speech spectrum that contains important phonetic information, which significantly contributes to the intelligibility of spoken language. Frequencies around this range help convey many consonants that are vital for distinguishing between different sounds and words.

This measure helps hearing professionals assess how well a person can understand speech in various listening situations, particularly in environments with background noise. The SII quantifies the proportion of speech information that is audible, focusing on the contributions of different frequency bands to overall intelligibility, with 2000 Hz being a key point of interest due to its substantial impact on speech clarity.

In contrast, the other options either refer to different measurements or frequency ranges that do not emphasize the same significant contribution to speech intelligibility. For instance, the Articulation Index at a higher frequency might not reflect the most crucial sounds for understanding speech, and similar reasoning applies to the Speech Recognition Score at lower frequencies that are not as effective for conveying critical speech information.